I'd recast him with some horrendous casting choice like Ted McGinley, just to piss off everyone.

Just pushing for that "shark jump" aren't you? Luckily, Batman's utility belt is equipped with a can of aerosol shark repellent. (As shown in the Adam West Batman movie)

If they need the Joker, recast Johnny Depp in the role. Get him away from Tim Burton and show him what a REAL Batman director can do! Seriously though, Depp could pull off the role in a similar take to Ledger's as well as a similar look. Yet I could also see him coming in and making a mark on the role all his own even given all of Ledger's marks he has to follow.